Known network operating facilities for personal computers and network servers support simultaneous connections (i.e. logical conversations) to other computers and computer networks via a plurality of adaptors. The ability to support a plurality of connections to various networks via the plurality of adaptors facilitates the maintenance of a direct connection to a local area network (LAN) and a wide area network (WAN). This ability of a networked computer to support a plurality of connections to a heterogenous set of networks presents the opportunity for the networked computer to route messages received on a WAN adaptor to a computer network linked to the networked computer via a LAN adaptor.
In prior known computer systems, a networked computer is statically connected to both a LAN and a WAN, the networked computer routes messages from a connected WAN to another computer on a connected LAN. The networked computer receives a network request via the WAN connection designating the LAN address and a destination network connected to the networked computer via a LAN adaptor. The networked computer creates a protocol header for the received network request in a known manner and forwards the network request on the LAN to the destination computer.
It is also known for a networked computer to act as a client of a WAN link. The networked computer acting as a client may send requests to a destination network connected via the WAN link. These requests may come from the networked computer or from other computers connected to a same LAN as the networked computer. The networked computer sends a network request to a remote computer network via the WAN connection. The remote request is received by the remote computer network and routed, if necessary to a destination network connected to the remote computer network. The routing of the network message to a computer on the remote network is accomplished by creating a protocol header for the received network request and then forwarding the network message to the specified destination network via the WAN link.
When a networked computer sends a packet under the known Inter-network Packet Exchange (IPX) protocol or other network transport protocols, packet headers contain a destination network number identifying a network to which a destination for the packet belongs. Under the IPX protocol, if the destination is on the same network as the sending computer, then a zero may be placed in the destination network field of the packet header.
If, however, the destination is located on another (remote) network, then the sending computer transmits a routing information protocol (RIP) request on the network to which the sending computer is directly connected (i.e., the "zero" network). The zero network RIP request is responded to by the routers on the sending computer's network which have a path to the destination network. The ability of computers to maintain paths to connected networks presents the possibility of maintaining an open-ended network to which additional networks may be connected via routing computers.
The ability of a networked computer to connect to an open ended set of networks under the IPX protocol is not without its drawbacks and/or limitations. First, IPX Network identifications are not globally administered, and thus do not guarantee that two distinct networks will have different network identifications. Therefore, it is possible for two connected networks to have a same network identification value because the network identification values typically fall within a very small set of values. As a consequence, more than one response to a RIP request may be received from routers connected to distinct networks having the same network identification.
A known manner for preventing two networks from having a same identification is to have a single administrator of network identification values which centrally governs the allocation of identification values to the connected networks and guarantees that the network numbers associated with each of the connected networks are non-overlapping. This solution is not a practical solution in an open-ended network connection environment where a networked computer may establish a connection to any of a number of remote networks via a WAN connection. In such cases, central administration of network numbers is simply not a practical solution since there is no guarantee that the connected network will allow the central administrator to allocate a network value to the network.
Second, if a sending computer connected to more than one network is asked to send a network zero request, then a question arises with respect to which network, of a plurality of connected networks, the packet is to be sent. One previously known solution is to send the request on all adaptors (connecting the sending computer to each of the networks). However, this assumes that there is no duplication of destination network identifications. This however, is not a valid assumption for non-centrally administered interconnected networks.
The ability of a networked personal computer to bind a WAN Adaptor and a LAN Adaptor clearly enhances the spectrum of possible uses for the networked computer. These uses include configuring the networked computer as a router for transferring packets between networks connected to the networked personal computer via LAN and WAN adaptors. However, the benefits of attaching a personal computer to other networks via a WAN adaptor and a LAN adaptor must be weighed against the uncertainty of whether all of the connected networks will be uniquely identified and the costs of solutions which ensure that all logically connected networks are uniquely identifiable.